A modern home includes many appliances and devices intended to provide comfort and convenience to the residents. For example, a home may include lighting equipment; security equipment; entertainment equipment; and heating, ventilation, and cooling (HVAC) equipment. However, most of this equipment has been developed separately and has separate and incompatible user interfaces and controls. To set the equipment to the user's desired settings, users must learn to use many different types of controls and may have to move back and forth between controls located at different locations throughout the house to achieve the desired result. A system is needed to provide a common interface to control a wide variety of equipment from one or more convenient locations.
There are many examples of inconveniences caused by separate and incompatible user interfaces. For example, each lamp usually has its own separate switch that must be operated to control the lamp. A television set may be equipped with a remote control, but that remote control might not be compatible with a remote control for a videocassette recorder. A sound system might require different remote controls for an amplifier and a compact disc player. A thermostat may be mounted at a single fixed location and require going to that location whenever an adjustment is desired. Thus, much effort is required to control devices having separate and incompatible user interfaces.
Various attempts have been made to overcome such inconveniences. For example, so-called universal infrared remote controls were developed to allow control of multiple audio-visual devices using a single infrared-emitting control. However, such a remote control does not control lights; heating, ventilation, and air conditioning equipment (HVAC), telephone lines, relay-controlled devices, devices with electrical serial data ports, or other devices. Moreover, such a remote control is not responsive to input from other devices, for example, devices emitting infrared signals. Also, an optical path must exist between such a remote control and an audio-visual device to be controlled since the infrared signal cannot penetrate walls or floors. Thus, infrared remote controls are ineffective for home automation.
Another attempted solution is referred to as the X-10 system. The X-10 system is a power line carrier communication system that superimposes a higher-frequency (i.e., 120 KHz) amplitude shift keyed (ASK) carrier over the 60 Hz power line frequency. X-10 devices are plugged into electrical outlets within a building. Sixteen X-10 commands are available to control X-10 devices. However, most X-10 devices recognize a subset of seven commands. X-10 devices are addressable using a four-bit “house” code designated by the letters A-P and a four-bit “unit” code designated by the numbers 1-16.
Since the X-10 system relies on a power line carrier, the performance of an X-10 system may be degraded by power line noise. Since pre-existing wiring in buildings was generally not specifically intended to be used with an X-10 system, the wiring topology of a building is often unknown, especially for older structures. Attenuation of power line carrier signals on a power line network is variable and often unpredictable, affecting the reliability of power line carrier transmission. Other power line carrier transmission techniques may interfere with X-10 signals. Because of the limited carrier frequency, the data transmission rates are slow, limiting use to situations where response time is not critical and where high data throughput is not important. At least one transmitter and a separate receiver for each controlled circuit are needed. Some X-10 devices have problems with data collisions during simultaneous transmissions. Thus, the X-10 system is of limited utility for home automation.
One type of system for providing control over network devices is known as the CEBus system. The CEBus system requires a network having distributed processing capability (i.e., an intelligent network). One of the problems associated with intelligent networks is that they are difficult to update with new information or configurations since intelligent nodes across the network must be updated, usually simultaneously. Updated information cannot simply be loaded into a single controller that controls the entire network. Each node of an intelligent network must be programmed to anticipate all possible combinations of node interaction within the network. Thus, if a new type of device for which the intelligent nodes are not programmed is introduced into the network, the intelligent nodes must be reprogrammed to be able to accommodate the new type of device as well as its range of possible interactions with other nodes on the network. Thus, networks having distributed processing capability generally require more maintenance and are more difficult to set up than master-slave based networks.
Another type of system for providing control over network devices is known as the Echelon LonWorks system. The Echelon system uses nodes that may operate in either a peer-to-peer mode (providing distributed control) or a master-slave mode (utilizing centralized control). Since the nodes possess computational capabilities, processing functions may be distributed throughout the system. Although the Echelon system may use existing electric power distribution wiring for communications, separate wiring is usually installed specifically to allow the Echelon nodes to communicate. When used in the peer-to-peer mode, the Echelon system also suffers the disadvantages associated with networks having distributed processing capabilities. Unfortunately, the peer-to-peer mode has been specified for use when interoperability of Echelon devices is desired. Some of the problems that can occur with the peer-to-peer mode include difficult setup, an increased processing power requirement at each node, and incompatibility of devices with future devices.
U.S. Pat. No. 6,574,234 (the '234 patent) discloses a method and apparatus for controlling devices on a network, such as household devices on a home automation network. In the disclosed system, a home automation network utilizes a central controller that provides control over one or more devices connected to the network. The central controller may be coupled to a computer, allowing the computer to program the central controller and to act as a redundant controller in case the central controller fails or is otherwise unable to effectively control the network. The central controller may communicate with devices and other equipment over a variety of types of networks, including EIA-485 balanced cabling and ethernet networks.
The '234 patent describes an identification mode that allows identification of devices and binding of physical devices to their corresponding representations used by the controller. The actual physical devices are referred to as hardware objects, while the representations used by the controller to represent the hardware objects are referred to as software objects. When a software object is being defined or selected, any hardware objects that are not already bound to a software object may be placed in an identification mode. In the identification mode, the unbound hardware objects provide an indication that they are unbound. A hardware object to be bound to the software object can then be easily selected from the unbound hardware objects.
Each of the foregoing systems suffers from limitations imposed by the communication medium. Power line-based communications are subject to interference and limited to outlet locations. Other line-based solutions require the provision of extra wiring to support the control network, limiting the flexibility of the control configuration (e.g., to add a new device, a new wire must also be added). The IR approach has line-of-sight limitations that prevent its effective use beyond the confines of a single room. The present inventors have identified that it would be desirable to have a control network that is not subject to such transmission media limitations, i.e., a control network that provides the flexibility to add, subtract and relocate control devices (or nodes) without changing the existing transmission infrastructure.
Another limitation on the flexibility of some existing control systems is the manner in which the controller interfaces with the vast array of appliance types possible. Typically, the control functionality is either implemented over a uniform interface, regardless of appliance type, or the controller uses a particular software object or device driver to interface with each appliance type. In the former case, control functionality is limited by the generic control instruction set used for every application. In the latter case, the controller or the system administrator (e.g., the homeowner) is typically required to identify an appropriate software object or device driver for controlling each new control device or node. The present inventors have identified that it would be desirable for the selection of a suitable device driver or software object to be automated when a new appliance control device is added to the control network.